There are a lot of legends about Kappa fighting the humans in the area of the Chikugo river 筑後川. But in the end the humans won and 九千坊河童 Kusengbo Kappa became the protector deity at this Suitengu Shrine.
So there are some prescriptions for the Shrine worshippers to prevent water accidents.

Before entering the water of a river you have to call out
"I am a heavenly messenger (mooshigo 申し子) sent from the Suitengu Shrine".
「水に入る前には水天宮の申し子だと唱える」

Other preventions from water accidents are :
- - not to eat mushrooms before entering the water
- - to have a bite from the rice offered at the Buddhist family altar 仏前飯

Kappa amulets of the shrine 河童面(かっぱめん)（箱・絵馬）
one mask comes in a box, the other on a votive tablet (ema).
They prevent evil influence and disasters. They must be hung in the demon-avoiding corner 鬼門 of the home.
Also 河童竹 and clay bells with the Kappa 河童鈴.